I. Field
The present disclosure relates generally to communication, and more specifically to techniques for supporting device-to-device (D2D) communications in conjunction with wide area network (WAN) communications.
II. Background
Wireless communication networks are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. Wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks. A wireless communication network may also be referred to as a wide area network (WAN).
Deployments of mobile wireless systems (mobile WANs) have been growing vigorously since at least the 1980s. Early systems used analog technology and comprised various technologies deployed in different systems worldwide, such as Analogue Mobile Phone System (AMPS), used in the USA, Total Access Communication System (TACS), used in parts of Europe, Nordic Mobile Telephone (NMT), used in parts of Europe, and Japanese Total Access Communication System (J-TACS), used in Japan and Hong Kong. Such systems came to be referred to as “First Generation” (1G) systems.
Global roaming became possible with the development of a so-called “Second Generation” (2G) system called the Global System for Mobile communications (GSM). GSM was based on digital technology rather than the analog technology of the earlier 1G systems. Under the aegis of the European Telecommunications Standards Institute (ETSI), GSM developed into a well-regarded and widely deployed standard.
Advances in mobile user equipment (UE) technology resulted in conveniently small battery powered handsets and the like, further advancing the widespread acceptance of personal mobile communications. However, radio frequency spectrum is a limited shared resource, governed by regulatory bodies such as the International Telecommunication Union-Radiocommunication sector (ITU-R) and other regional and national regulators, all of whom determine in their respective jurisdictions how to allocate the radio frequency spectrum among the different types of services and technologies that seek to use it. This role is facilitated by the standardization of radio technologies. Among other things, standardization encourages interoperability of equipment from multiple vendors, fostering competition and resulting in reduced equipment cost. Standardization also promotes the efficient use of radio spectrum and the deployment of new and improved services.
The ITU-R has defined technology families and has associated specific ranges of the radio spectrum with these families. Two such families are the International Mobile Telecommunications (IMT) family, which includes so-called “Third Generation” (3G) systems; and the IMT-Advanced (IMT-A) family, which includes “Fourth Generation” (4G) systems. The designation of each new generation refers generally to a fundamental change in the nature of the technologies used, e.g., different multiple access schemes resulting in non-backwards-compatible transmission technology, higher peak bitrates, different frequency bands, wider channel frequency bandwidth, and higher capacity. New mobile generations have been introduced about every ten years since the early 1980s, when analog 1G systems were deployed. In the early 1990s, digital 2G systems were deployed. In the early 2000s, 3G systems using spread spectrum communication were deployed. In the early 2010s, 4G systems based entirely on packet-switched (PS) technology are being deployed.
A wireless communication network in accordance with the foregoing standards may include a number of base stations (also referred to as evolved Node Bs, eNBs, BSs, or access nodes) that can support communication for a number of UEs. In such a WAN, communication by UEs typically occurs via uplink/downlink channels between the UEs and a base station.
However, if two UEs are in the vicinity of each other, they may be enabled to communicate directly, that is, without communicating through the base station. A UE may thus be enabled to communicate peer-to-peer (P2P), also referred to as device-to-device (D2D), with one or more other UEs.
It may be thus desirable to efficiently support P2P and base station communications for UEs, such as by enabling new types of services, improving available services, eliminating interference, and/or reducing the traffic load on base stations.